LTC3839 Fast, Accurate, 2-Phase, Single-Output Step-Down DC/DC Controller with Differential Output Sensing DESCRIPTION FEATURES n n n n n n n n n n n n n Wide VIN Range: 4.5V to 38V, VOUT: 0.6V to 5.5V ±0.
LTC3839 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) SW2 TG2 BOOST2 RUN SGND SENSE2– VRNG SENSE2+ TOP VIEW VIN Voltage ................................................. –0.3V to 40V BOOST1, BOOST2 Voltages ....................... –0.3V to 46V SW1, SW2 Voltages ...................................... –5V to 40V INTVCC, DRVCC1, DRVCC2, EXTVCC, PGOOD, RUN, (BOOST1-SW1), (BOOST2-SW2), MODE/PLLIN Voltages ....................................................... –0.
LTC3839 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. VIN = 15V unless otherwise noted (Note 3). SYMBOL PARAMETER CONDITIONS TYP MAX UNITS IVOUTSENSE+ VOUTSENSE+ Input Bias Current VOUTSENSE+ – VOUTSENSE– = 0.6V MIN ±5 ±25 nA IVOUTSENSE– VOUTSENSE– Input Bias Current VOUTSENSE+ – VOUTSENSE– = 0.6V –25 –50 gm(EA) Error Amplifier Transconductance ITH = 1.
LTC3839 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. VIN = 15V unless otherwise noted (Note 3). SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Internally Regulated DRVCC1 Voltage 6V < VIN < 38V 5.0 5.3 5.6 V DRVCC1 Load Regulation IDRVCC1 = 0mA to –100mA –1.5 –3.5 % EXTVCC Switchover Voltage EXTVCC Rising 4.6 4.
LTC3839 TYPICAL PERFORMANCE CHARACTERISTICS Transient Response (Forced Continuous Mode) Load Step (Forced Continuous Mode) ILOAD 20A/DIV ILOAD 20A/DIV VOUT 50mV/DIV VOUT 50mV/DIV IL1 10A/DIV IL2 10A/DIV IL1 10A/DIV IL2 10A/DIV 50μs/DIV LOAD TRANSIENT = 0A TO 30A VIN = 12V VOUT = 1.2V FIGURE 17 CIRCUIT 3839 G01 ILOAD 20A/DIV VOUT 50mV/DIV IL1 10A/DIV IL2 10A/DIV 5μs/DIV LOAD STEP = 0A TO 30A VIN = 12V VOUT = 1.
LTC3839 TYPICAL PERFORMANCE CHARACTERISTICS Soft Start-Up Into Pre-Biased Output Regular Soft Start-Up RUN 5V/DIV RUN 5V/DIV TRACK/SS 200mV/DIV VOUT 500mV/DIV TRACK/SS 200mV/DIV CSS = 10nF 1ms/DIV VIN = 12V VOUT = 1.2V FORCED CONTINUOUS MODE 3839 G09 CSS = 10nF 1ms/DIV VIN = 12V VOUT = 1.2V VOUT PRE-BIASED TO 0.
LTC3839 TYPICAL PERFORMANCE CHARACTERISTICS Output Regulation vs Input Voltage Output Regulation vs Load Current 0.2 0.2 0.6 VIN = 15V VOUT = 0.6V VOUT NORMALIZED AT ILOAD = 8A 0.1 0 –0.1 0.1 NORMALIZED ΔVOUT (%) NORMALIZED ΔVOUT (%) VOUT = 0.6V ILOAD = 5A VOUT NORMALIZED AT VIN = 15V NORMALIZED ΔVOUT (%) Output Regulation vs Temperature 0 VIN = 15V VOUT = 0.6V 0.4 ILOAD = 0A VOUT NORMALIZED AT TA = 25°C 0.2 0 –0.2 –0.1 –0.4 –0.2 –0.
LTC3839 TYPICAL PERFORMANCE CHARACTERISTICS FORCED CONTINUOUS MODE CURRENT SENSE VOLTAGE (mV) 100 80 60 40 20 0 –20 VRNG = 2V VRNG = 1V VRNG = 0.6V –40 –60 0 0.8 1.2 1.6 ITH VOLTAGE (V) 0.4 120 VRNG = 2V 100 80 60 VRNG = 1V 40 VRNG = 0.6V 20 0 –50 –25 2.4 2 0 25 50 75 100 125 150 TEMPERATURE (°C) RUN Pin Thresholds vs Temperature 0.8 0.6 6 RUN PIN BELOW 1.2V SWITCHING THRESHOLD 1.05 1.00 0.95 0.85 0 –50 –25 25 50 75 100 125 150 TEMPERATURE (°C) 0 0.
LTC3839 PIN FUNCTIONS PHASMD (Pin 1): Phase Selector Input. This pin determines the relative phases of channels and the CLKOUT signal. With zero phase being defined as the rising edge of TG1: Pulling this pin to SGND locks TG2 to 180°, and CLKOUT to 60°. Connecting this pin to INTVCC locks TG2 to 240° and CLKOUT to 120°. Floating this pin locks TG2 to 180° and CLKOUT to 90°. MODE/PLLIN (Pin 2): Operation Mode Selection or External Clock Synchronization Input.
LTC3839 PIN FUNCTIONS PGOOD (Pin 13): Power Good Indicator Output. This open-drain logic output is pulled to ground when the output voltage goes out of a ±7.5% window around the regulation point, after a 50μs power-bad-masking delay. Returning to the regulation point, there is a 20μs delay to power good, and a hysteresis of around 2% on both sides of the voltage window. BOOST1, BOOST2 (Pin 14, Pin 27): Boosted Floating Supplies for Top MOSFET Drivers.
LTC3839 FUNCTIONAL DIAGRAM VIN VIN IN EN LDO 2-5μA PTAT OUT SD 10μA + UVLO 4.2V + 1.2V BOOST TG DRV – RUN MT L SW EN_DRV – CB DB TG RSENSE VOUT DRVCC ~0.8V – – LOGIC CONTROL SENSE– VIN 250k FORCED CONTINUOUS MODE ~4.
LTC3839 OPERATION (Refer to Functional Diagram) Main Control Loop The LTC3839 is a controlled on-time, valley current mode step-down DC/DC single-output controller with two channels operating out of phase. Each channel drives both main and synchronous N-channel MOSFETs. The top MOSFET is turned on for a time interval determined by a one-shot timer. The duration of the one-shot timer is controlled to maintain a fixed switching frequency.
LTC3839 OPERATION (Refer to Functional Diagram) Characteristics Table), then the internal 5.3V LDO is enabled. If the EXTVCC pin is tied to an external voltage source greater than this EXTVCC switchover voltage, then the LDO is shut down and the internal EXTVCC switch shorts the EXTVCC pin to the DRVCC2 pin, thereby powering DRVCC and INTVCC with the external voltage source and helping to increase overall efficiency and decrease internal self heating from power dissipated in the LDO.
LTC3839 OPERATION (Refer to Functional Diagram) Power Good and Fault Protection The PGOOD pin is connected to an internal open-drain N-channel MOSFET. An external resistor or current source can be used to pull this pin up to 6V (e.g., VOUT or DRVCC). Overvoltage or undervoltage comparators (OV, UV) turn on the MOSFET and pull the PGOOD pin low when the feedback voltage is outside the ±7.5% window of the 0.6V reference voltage. The PGOOD pin is also pulled low when the RUN pin is below the 1.
LTC3839 OPERATION (Refer to Functional Diagram) Multichip Operation Table 2 The PHASMD pin determines the relative phases between the internal reference clock signals for the two channels as well as the CLKOUT signal, as shown in Table 1. The phases tabulated are relative to zero degree (0°) being defined as the rising edge of the internal reference clock signal of channel 1.
LTC3839 APPLICATIONS INFORMATION Once the required output voltage and operating frequency have been determined, external component selection is driven by load requirement, and begins with the selection of inductors and current sense method (either sense resistors RSENSE or inductor DCR sensing). Next, power MOSFETs are selected. Finally, input and output capacitors are selected.
LTC3839 APPLICATIONS INFORMATION CIN MT + – VIN POWER TRACE PARASITICS L LTC3839 VOUTSENSE+ VOUTSENSE– RFB2 ±VDROP(PWR) MB RFB1 COUT1 ILOAD COUT2 I LOAD GROUND TRACE PARASITICS ±VDROP(GND) OTHER CURRENTS FLOWING IN SHARED GROUND PLANE 3839 F02 Figure 2. Differential Output Sensing Used to Correct Line Loss Variations in a High Power Distributed System with a Shared Ground Plane to maintain low output ripple voltage.
LTC3839 APPLICATIONS INFORMATION Inductor Core Selection Current Limit Programming Once the value for L is known, the type of inductor must be selected. The two basic types are iron powder and ferrite. The iron powder types have a soft saturation curve which means they do not saturate hard like ferrites do. However, iron powder type inductors have higher core losses.
LTC3839 APPLICATIONS INFORMATION recommended lower limits of VSENSE(MAX) (by each individual channel, calculated as half of the 2-channel-sum) for statistical tolerancing design of a 2-phase application are: • 24mV at VRNG = 0.6V or SGND (30mV typical); • 42mV at VRNG = 1V or INTVCC (50mV typical); • 85mV at VRNG = 2V (100mV typical). Either worst-case or statistical limits can be chosen to establish absolute minimums for current limit of the LTC3839.
LTC3839 APPLICATIONS INFORMATION filter placed near the IC has been traditionally used to reduce the effects of capacitive and inductive noise coupled in the sense traces on the PCB. A typical filter consists of two series 10Ω resistors connected to a parallel 1000pF capacitor, resulting in a time constant of 20ns. This same RC filter, with minor modifications, can be used to extract the resistive component of the current sense signal in the presence of parasitic inductance.
LTC3839 APPLICATIONS INFORMATION as a differential pair and Kelvin (4-wire) connected to the sense resistor. DCR Inductor Current Sensing For applications requiring higher efficiency at high load currents, the LTC3839 is capable of sensing the voltage drop across the inductor DCR, as shown in Figure 5. The DCR of the inductor represents the small amount of DC winding resistance, which can be less than 1mΩ for today’s low value, high current inductors.
LTC3839 APPLICATIONS INFORMATION To maintain a good signal-to-noise ratio for the current sense signal, start with a ∆VSENSE of 10mV. For a DCR sensing application, the actual ripple voltage will be determined by: V –V V ΔVSENSE = IN OUT • OUT R1• C1 VIN • f Power MOSFET Selection Two external N-channel power MOSFETs must be selected for each channel of the LTC3839 controller: one for the top (main) switch and one for the bottom (synchronous) switch. The gate drive levels are set by the DRVCC voltage.
LTC3839 APPLICATIONS INFORMATION LIN 1μH + – VIN ESR(BULK) ESR(CERAMIC) ESL(BULK) ESL(CERAMIC) IPULSE(PHASE1) IPULSE(PHASE2) + CIN(BULK) CIN(CERAMIC) 3839 F06 Figure 6. Circuit Model for Input Capacitor Ripple Current Simulation For simulations with this model, look at the ripple current during steady-state for the case where one phase is fully loaded and the other was not loaded.
LTC3839 APPLICATIONS INFORMATION Figure 7 shows that the use of more phases will reduce the ripple current through the input capacitors due to ripple current cancellation. However, since LTC3839 is only truly phase-interleaved at steady state, transient RMS currents could be higher than the curves for the designated number of phase. Therefore, it is advisable to choose capacitors by taking account the specific load situations of the applications.
LTC3839 APPLICATIONS INFORMATION For high switching frequencies, reducing output ripple and better EMI filtering may require small value capacitors that have low ESL (and correspondingly higher self-resonant frequencies) to be placed in parallel with larger value capacitors that have higher ESL. This will ensure good noise and EMI filtering in the entire frequency spectrum of interest.
LTC3839 APPLICATIONS INFORMATION However, for 3.3V and other low voltage outputs, additional circuitry is required to derive DRVCC power from the converter output. The following list summarizes the four possible connections for EXTVCC: 1. EXTVCC left open (or grounded). This will cause INTVCC to be powered from the internal 5.3V LDO resulting in an efficiency penalty of up to 10% at high input voltages. 2.
LTC3839 APPLICATIONS INFORMATION As voltage on the RUN pin increases, typically beyond 3V, its bias current will start to reverse direction and flow into the RUN pin. Keep in mind that the RUN pin can sink up to 50μA; Even if a RUN pin may slightly exceed 6V when sinking 50μA, the RUN pin should never be forced to higher than 6V by a low impedance voltage source to prevent faulty conditions. When the LTC3839 is configured to soft-start by itself, a capacitor should be connected to its TRACK/SS pin.
LTC3839 APPLICATIONS INFORMATION When the LTC3839 is configured to track an external supply, a voltage divider can be used from the external supply to the TRACK/SS pin to scale the ramp rate appropriately. Two common implementations are coincidental tracking and ratiometric tracking. For coincident tracking, make the divider ratio from the external supply the same as the divider ratio for the differential feedback voltage.
LTC3839 APPLICATIONS INFORMATION to INTVCC, it will operate in forced continuous mode at the RT-programmed frequency. If the MODE/PLLIN pin is tied to SGND, the LTC3839 will operate in discontinuous mode at light load and switch into continuous conduction at the RT programmed frequency as load increases. The TG on-time during discontinuous conduction is intentionally slightly extended (approximately 1.
LTC3839 APPLICATIONS INFORMATION conditions of the switching regulator. One of the factors that contributes to this discrepancy is the characteristics of the power MOSFETs. For example, if the top power MOSFET’s turn-on delay is much smaller than the turn-off delay, the effective on-time will be longer than the TG on-time, limiting the effective minimum on-time to a larger value.
LTC3839 APPLICATIONS INFORMATION BG off to TG on. The minimum off-time that the LTC3839 can achieve is 90ns. The effective minimum off-time of the switching regulator, or the shortest period of time that the SW node can stay low, can be different from this minimum off-time. The main factor impacting the effective minimum off-time is the top and bottom power MOSFETs’ electrical characteristics, such as Qg and turn-on/off delays.
LTC3839 APPLICATIONS INFORMATION response test point. The DC step, rise time and settling at this test point truly reflects the closed-loop response. Assuming a predominantly 2nd order system, phase margin and/or damping factor can be estimated using the percentage of overshoot seen at this pin. The external series RITH-CITH1 filter at the ITH pin sets the dominant pole-zero loop compensation.
LTC3839 APPLICATIONS INFORMATION If the bottom MOSFET could be turned off during the loadrelease transient, the inductor current would flow through the body diode of the bottom MOSFET, and the equation can be modified to include the bottom MOSFET body diode drop to become VL = –(VOUT + VBD). Obviously the benefit increases as the output voltage gets lower, since VBD would increase the sum significantly, compared to a single VOUT only.
LTC3839 APPLICATIONS INFORMATION The DTR comparator output is overridden by reverse inductor current detection (IREV) and overvoltage (OV) condition. This means BG will be turned off when SENSE+ is higher than SENSE– (i.e., inductor current is positive), as long as the OV condition is not present. When inductor current drops to zero and starts to reverse, BG will turn back on in forced continuous mode (e.g.
LTC3839 APPLICATIONS INFORMATION where Qg(TOP) and Qg(BOT) are the gate charges of the top and bottom MOSFETs, respectively. Supplying DRVCC power through EXTVCC could save several percents of efficiency, especially for high VIN applications. Connecting EXTVCC to an output-derived source will scale the VIN current required for the driver and controller circuits by a factor of (Duty Cycle)/ (Efficiency). For example, in a 20V to 5V application, 10mA of DRVCC current results in approximately 2.
LTC3839 APPLICATIONS INFORMATION VIN 4.5V TO 26V + CIN2 10μF w3 CIN1 220μF 2.2Ω LTC3839 1μF VIN SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 0.1μF 15k 0.1μF 0.1μF 0.1μF 3.57k VOUT 1.2V 30A TG1 MT1 L1 0.56μH + 3.57k TG2 MT2 DB1 DB2 SW1 2.2Ω COUT1 100μF w2 1μF L2 0.56μH SW2 DRVCC1 INTVCC COUT2 330μF w2 15k DRVCC2 EXTVCC COUT4 + 330μF w2 4.7μF BG1 MB1 BG2 MB2 COUT3 100μF w2 PGND 10k VOUTSENSE+ 10k 100k VOUTSENSE– PGOOD 0.01μF PHASMD TRACK/SS 22pF 90.
LTC3839 APPLICATIONS INFORMATION Often in a high power application, DCR current sensing is preferred over RSENSE in order to maximize efficiency. In order to determine the DCR filter values, first the inductor manufacturer has to be chosen. For this design, the Vishay IHLP-4040DZ-01 model is chosen with a value of 0.56μH and a DCRMAX =1.8mΩ. This implies that: VSENSE(MAX) = 1.8mΩ • [1 + (100°C – 25°C) • 0.4%/°C] • (15A – 5.
LTC3839 APPLICATIONS INFORMATION Select the CIN capacitors to give ample capacitance and RMS ripple current rating. Consider worst-case duty cycles per Figure 6: If operated at steady-state with SW nodes fully interleaved, the two channels would generate not more than 7.5A RMS at full load. In this design example, 3 × 10μF ceramic capacitors are put in parallel to take the RMS ripple current, with a 220μF aluminum-electrolytic bulk capacitor for stability.
LTC3839 APPLICATIONS INFORMATION L2 RSENSE2 CB2 MT2 SENSE2+ VRNG PHASMD SGND RUN BOOST2 TG2 CERAMIC DB2 LTC3839 DRVCC2 CLKOUT LOCALIZED SGND TRACE MB2 SW2 BG2 MODE/PLLIN EXTVCC SGND COUT2 INTVCC + RT RITH1 SENSE2– RT CITH1 PGND ITH PGND VIN CERAMIC DRVCC1 TRACK/SS VOUT + VIN CSS PGND + CIN CVIN RVIN RITH2 COUT1 DB1 VOUTSENSE+ BG1 VOUTSENSE– SENSE1+ SENSE1– DTR PGOOD BOOST1 TG1 SW1 RFB1 MT1 MB1 CB1 RFB2 RSENSE1 L1 3839 F14 BOLD LINES INDICATE HIGH S
LTC3839 APPLICATIONS INFORMATION • All power train components should be referenced to PGND; all components connected to noise-sensitive pins, e.g., ITH, RT , TRACK/SS and VRNG, should return to the SGND pin. Keep PGND ample, but SGND area compact. Use a modified “star ground” technique: a low impedance, large copper area central PCB point on the same side of the as the input and output capacitors. • Place power components, such as CIN, COUT , MOSFETs, DB and inductors, in one compact area.
LTC3839 APPLICATIONS INFORMATION these pins. If the IC can be placed on the bottom side of a multilayer board, use ground planes to isolate from the major power components on the top side of the board, and prevent noise coupling to noise sensitive components on the bottom side. • Place the resistor feedback divider RFB1, RFB2 close to VOUTSENSE1+ and VOUTSENSE1– pins, so that the feedback voltage tapped from the resistor divider will not be disturbed by noise sources.
LTC3839 APPLICATIONS INFORMATION The capacitor placed across the current sensing pins needs to be placed immediately adjacent to the pins of the IC. This capacitor helps to minimize the effects of differential noise injection due to high frequency capacitive coupling. If problems are encountered with high current output loading at lower input voltages, look for inductive coupling between CIN, top and bottom MOSFET components to the sensitive current and voltage sensing traces.
LTC3839 TYPICAL APPLICATIONS VIN 4.5V TO 38V + CIN2 10μF w3 CIN1 100μF 2.2Ω 1μF VIN LTC3839 SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 0.1μF 15k 0.1μF 0.1μF 0.1μF 3.57k VOUT 1.2V 30A TG1 MT1 L1 0.56μH + 3.57k TG2 MT2 DB1 SW1 SW2 DRVCC1 INTVCC COUT2 330μF w2 1μF L2 0.56μH DB2 2.2Ω COUT1 100μF w2 15k DRVCC2 EXTVCC COUT4 + 330μF w2 4.7μF BG1 MB1 BG2 MB2 COUT3 100μF w2 PGND 10k VOUTSENSE+ 10k 100k VOUTSENSE– PGOOD 0.
LTC3839 TYPICAL APPLICATIONS VIN 6V TO 26V + CIN1 220μF CIN2 10μF w3 2.2Ω LTC3839 1μF VIN 20Ω SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 20Ω 1nF 20Ω 1nF 0.1μF 0.1μF RS1 0.002Ω VOUT 1.2V 30A MT1 L1 0.47μH TG1 + COUT2 330μF w2 MT2 TG2 DB2 DB1 SW1 2.2Ω COUT1 100μF w2 20Ω DRVCC2 EXTVCC COUT3 330μF w2 4.7μF MB1 RS2 0.002Ω SW2 DRVCC1 INTVCC 1μF L2 0.47μH BG1 MB2 BG2 + COUT4 100μF w2 PGND 10k VOUTSENSE+ 10k VOUTSENSE– 100k PGOOD 0.01μF 60.
LTC3839 TYPICAL APPLICATIONS VIN 4.5V TO 14V + CIN2 22μF w4 CIN1 180μF 2.2Ω LTC3839 1μF VIN SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 0.1μF 0.1μF 0.1μF 0.1μF 2.55k L1 0.33μH VOUT 1.2V 50A MT1 TG1 DB2 DB1 SW1 2.2Ω COUT1 100μF w2 + COUT2 330μF w2 2.55k MT2 TG2 L2 0.33μH SW2 DRVCC1 INTVCC DRVCC2 EXTVCC 4.7μF 1μF MB1 BG1 MB2 BG2 COUT3 + 330μF w2 COUT4 100μF w2 PGND 10k VOUTSENSE+ 10k VOUTSENSE– 100k PGOOD 0.
LTC3839 TYPICAL APPLICATIONS VIN 6.5V TO 34V + CIN1 56μF w3 CIN2 10μF w3 2.2Ω LTC3839 1μF VIN 20Ω SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 20Ω 1nF 20Ω 1nF 0.1μF 0.1μF RS1 0.002Ω VOUT 5V 25A L1 2.2μH MT1 TG1 + COUT2 150μF w2 MT2 TG2 DB1 DB2 SW1 2.2Ω COUT1 100μF 20Ω L2 2.2μH SW2 DRVCC1 INTVCC DRVCC2 EXTVCC VOUT 4.7μF 1μF MB1 RS2 0.002Ω BG1 MB2 BG2 COUT3 150μF w2 + COUT4 100μF PGND 73.2k VOUTSENSE+ 10k VOUTSENSE– 100k PGOOD 0.01μF PGOOD 22pF ITH 27.
LTC3839 TYPICAL APPLICATIONS VIN 4.5V TO 14V + CIN2 22μF w4 CIN1 180μF 2.2Ω LTC3839 1μF VIN 10Ω SENSE1– SENSE2– SENSE1+ SENSE2+ BOOST1 BOOST2 10Ω 1nF 10Ω 1nF 0.1μF L1 0.3μH RS1 0.004Ω VOUT 3.3V 25A 0.1μF MT1 TG1 MT2 TG2 DB1 SW1 RS2 0.004Ω SW2 DRVCC1 INTVCC 1μF L2 0.3μH DB2 2.2Ω COUT1 100μF w6 10Ω DRVCC2 EXTVCC 4.7μF MB1 BG1 MB2 BG2 PGND 45.
LTC3839 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. UH Package 32-Lead Plastic QFN (5mm × 5mm) (Reference LTC DWG # 05-08-1693 Rev D) 0.70 p0.05 5.50 p0.05 4.10 p0.05 3.45 p 0.05 3.50 REF (4 SIDES) 3.45 p 0.05 PACKAGE OUTLINE 0.25 p 0.05 0.50 BSC RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 p 0.10 (4 SIDES) BOTTOM VIEW—EXPOSED PAD 0.75 p 0.05 R = 0.05 TYP 0.00 – 0.05 PIN 1 NOTCH R = 0.
LTC3839 REVISION HISTORY REV DATE DESCRIPTION A 6/12 Electrical specs clarification, 4.6V EXTVCC switch over PAGE NUMBER 3, 4, 10, 11 3839fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LTC3839 TYPICAL APPLICATION 4.5V to 14V Input, 0.6V/30A Output, 400kHz, RSENSE, DTR Enabled, Step-Down Converter VIN 4.5V TO 14V + CIN1 180μF CIN2 22μF w3 2.2Ω LTC3839 1μF VIN 20Ω SENSE1– SENSE2– SENSE1+ SENSE2+ 1nF 20Ω 1nF BOOST1 VOUT 0.6V 30A L1 0.22μH MT1 + BOOST2 TG1 DB2 SW1 1μF L2 0.22μH RS2 0.002Ω SW2 DRVCC1 INTVCC COUT2 330μF w4 MT2 TG2 DB1 2.2Ω COUT1 100μF w4 20Ω 0.1μF 0.1μF RS1 0.002Ω 20Ω DRVCC2 EXTVCC 4.
